This episode's headline: Food for Oil?; Filtering Smut; Hepatitis C; Fighting AIDS. ANCHOR: MARGARET WARNER; GUESTS: EDMUND GHAREEB, American University; PHEBE MARR, National Defense University; STEVEN LEVY, Newsweek; DR. STEFANO BERTOZZI, UNAIDS; CORRESPONDENTS: SPENCER MICHELS; KWAME HOLMAN; PHIL PONCE; FRED DE SAM LAZARO; ELIZABETH FARNSWORTH;